The present invention relates to an image-forming apparatus such as a copier, a printer, a fax machine, a plotter device, or an electrophotographic printer used for a multifunctional peripheral of those.
As the above image-forming apparatus, an image-forming apparatus using a corona-charging type charging device as a charging device which charges a surface of a photoconductor as an image bearer is known. In a case of the corona-charging type, ozone and a substance of nitrates as a discharge product generated by corona discharge form a coating film on the photoconductor. When the coating film absorbs moisture in the air, a surface resistance of the photoconductor lowers, a part of, or an entire electrostatic latent image is not maintained and ruined in a surface direction of a surface of the photoconductor, and becomes a blurred image as a letter written in ink on a wet paper. Such a phenomenon is referred to as image deletion.
The image deletion often occurs under the following conditions in which a moisture amount absorbed by a photoconductor is easily increased.
(1) a case where a stop time of the image-forming apparatus is long after the image-forming apparatus operates.
(2) a case where absolute humidity is high in an installation environment of the image-forming apparatus.
In order to release the ozone and the discharge product which cause the image deletion, an air-blowing device which sucks outside air into the charging device, and releases the sucked outside air, the ozone, and the discharge product concurrently is provided in the image-forming apparatus conventionally. The air-blowing device operates when the power of the image forming apparatus is turned off, and except when the image-forming apparatus is in a power-saving mode to which the image-forming apparatus is switched when the power is left on and the image-forming apparatus is unused for a certain time.
In this case, for a certain time after an end of an image-forming operation, the air-blowing device keeps an operating state, and when the certain time elapses after the end of the image-forming operation, the air-blowing device automatically stops, and the image-forming apparatus is switched to the power-saving mode.
However, when an operator turns the power off before the image-forming apparatus is switched to the power-saving mode, there is a case where the air-blowing device does not operate for the certain time after the end of the image-forming operation. In this case, there is a case where release of the ozone and the discharge product is not sufficiently performed, and compared to a case where the air-blowing device operates for the certain time after the end of the image-forming operation, the image deletion tends to occur, and even if a polishing operation of the photoconductor is executed as usual, there is a case where the image deletion occurs.